<!DOCTYPE html>
<htm1><head><meta charset="utf-8" /><title></title>
    <style type="text/css">
    #pl{font-weight: 100;} 
    #p2{font-weight: 400;}
    #p3{font-weight: 700;}
    #p4{font-weight: 900;}
    </style></head>
    <body>
    <p  id="p1">字体粗细为:100(1ighter) </p >
    <p  id="p2">字体粗细为:400(normal)</p >
    <p  id="p3">字体粗细为:700( bold)</p >
    <p id="p4">字体粗细为:900( bolder)</p >
    </body>
    </html>